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OpenCV/include/opencv2/gapi/gscalar.hpp

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+// This file is part of OpenCV project.
+
+// It is subject to the license terms in the LICENSE file found in the top-level directory
+// of this distribution and at http://opencv.org/license.html.
+//
+// Copyright (C) 2018 Intel Corporation
+
+
+#ifndef OPENCV_GAPI_GSCALAR_HPP
+#define OPENCV_GAPI_GSCALAR_HPP
+
+#include <ostream>
+
+#include <opencv2/gapi/opencv_includes.hpp>
+#include <opencv2/gapi/gcommon.hpp> // GShape
+#include <opencv2/gapi/util/optional.hpp>
+
+namespace cv
+{
+// Forward declaration; GNode and GOrigin are an internal
+// (user-inaccessible) classes.
+class GNode;
+struct GOrigin;
+
+/** \addtogroup gapi_data_objects
+ * @{
+ */
+/**
+ * @brief GScalar class represents cv::Scalar data in the graph.
+ *
+ * GScalar may be associated with a cv::Scalar value, which becomes
+ * its constant value bound in graph compile time. cv::GScalar describes a
+ * functional relationship between operations consuming and producing
+ * GScalar objects.
+ *
+ * GScalar is a virtual counterpart of cv::Scalar, which is usually used
+ * to represent the GScalar data in G-API during the execution.
+ *
+ * @sa Scalar
+ */
+class GAPI_EXPORTS_W_SIMPLE GScalar
+{
+public:
+    /**
+     * @brief Constructs an empty GScalar
+     *
+     * Normally, empty G-API data objects denote a starting point of
+     * the graph. When an empty GScalar is assigned to a result of some
+     * operation, it obtains a functional link to this operation (and
+     * is not empty anymore).
+     */
+    GAPI_WRAP GScalar();
+
+    /**
+     * @brief Constructs a value-initialized GScalar
+     *
+     * In contrast with GMat (which can be either an explicit graph input
+     * or a result of some operation), GScalars may have their values
+     * be associated at graph construction time. It is useful when
+     * some operation has a GScalar input which doesn't change during
+     * the program execution, and is set only once. In this case,
+     * there is no need to declare such GScalar as a graph input.
+     *
+     * @note The value of GScalar may be overwritten by assigning some
+     * other GScalar to the object using `operator=` -- on the
+     * assignment, the old GScalar value is discarded.
+     *
+     * @param s a cv::Scalar value to associate with this GScalar object.
+     */
+    explicit GScalar(const cv::Scalar& s);
+
+    /**
+     * @overload
+     * @brief Constructs a value-initialized GScalar
+     *
+     * @param s a cv::Scalar value to associate with this GScalar object.
+     */
+    explicit GScalar(cv::Scalar&& s);       // Constant value move-constructor from cv::Scalar
+
+    /**
+     * @overload
+     * @brief Constructs a value-initialized GScalar
+     *
+     * @param v0 A `double` value to associate with this GScalar. Note
+     *  that only the first component of a four-component cv::Scalar is
+     *  set to this value, with others remain zeros.
+     *
+     * This constructor overload is not marked `explicit` and can be
+     * used in G-API expression code like this:
+     *
+     * @snippet samples/cpp/tutorial_code/gapi/doc_snippets/api_ref_snippets.cpp gscalar_implicit
+     *
+     * Here operator+(GMat,GScalar) is used to wrap cv::gapi::addC()
+     * and a value-initialized GScalar is created on the fly.
+     *
+     * @overload
+     */
+    GScalar(double v0);                                // Constant value constructor from double
+
+    /// @private
+    GScalar(const GNode &n, std::size_t out);          // Operation result constructor
+    /// @private
+    GOrigin& priv();                                   // Internal use only
+    /// @private
+    const GOrigin& priv()  const;                      // Internal use only
+
+private:
+    std::shared_ptr<GOrigin> m_priv;
+};
+
+/** @} */
+
+/**
+ * \addtogroup gapi_meta_args
+ * @{
+ */
+struct GAPI_EXPORTS_W_SIMPLE GScalarDesc
+{
+    // NB.: right now it is empty
+
+    inline bool operator== (const GScalarDesc &) const
+    {
+        return true; // NB: implement this method if GScalar meta appears
+    }
+
+    inline bool operator!= (const GScalarDesc &rhs) const
+    {
+        return !(*this == rhs);
+    }
+};
+
+GAPI_EXPORTS_W inline GScalarDesc empty_scalar_desc() { return GScalarDesc(); }
+
+GAPI_EXPORTS GScalarDesc descr_of(const cv::Scalar &scalar);
+
+std::ostream& operator<<(std::ostream& os, const cv::GScalarDesc &desc);
+
+} // namespace cv
+
+#endif // OPENCV_GAPI_GSCALAR_HPP